Hand-timed vs. Electronic-timed 40 yard dash

We’re in the midst of the football off-season where athletes are getting up bright and early to train for next season. High school players are trying to lock down scholarships to major Universities while collegiate athletes are trying to make a name for themselves at the NFL and various free agent combines. This also means that we’re around the corner from all of the reports of incredible 40-yard sprint times. You know, all the sub-4.4 times that kids coming out of high school are running.

Fortunately there is some new research to remind us all that nearly all of these incredible 40-yard dash times are hand-timed with a stop watch, and therefore hyper-inflated. In an article published ahead of print in the Journal of Strength and Conditioning Research, Mann and colleagues (2015) compared hand-timed versus electronic-timed 40-yard dash attempts in 81 division-1 NCAA football players. Additionally, the researchers compared novice versus experienced coaches for hand-time accuracy. The smallest worthwhile difference was then calculated to determine what a meaningful change in sprint time was that exceeds expected noise.

The results showed the hand-timed 40-yard dashes were significantly faster compared to electronic-timed (4.90 ± 0.34 s vs. 5.12 ± 0.35 s, respectively). A difference of 0.22 seconds! The novice coaches produced the fastest sprint times (4.86 ± 0.33 s). Interestingly, the reliability for hand-timed 40’s was quite high (Intraclass Correlation values >0.90). The smallest worthwhile difference for hand and electronic-timed 40-yard dashes was 0.14 and 0.12 seconds, respectively.

Next time you hear about an unbelievable 40 time from a high school athlete, more often than not, you needn’t believe it. If the run was hand-timed you can add between 0.22 and 0.26 seconds depending on if it was an experienced or novice coach. So that 4.3 s 40 time that you hear about is probably actually >4.5 s. However, even though hand-timing isn’t very accurate, it is apparently quite consistent. Therefore, it is likely that hand-timed 40’s will allow you to accurately rank players according to speed. Finally, when assessing changes in sprint performance among collegiate football players, a 0.12 second change is considered practically meaningful for electronic timing while a 0.14 second change is the threshold for hand-timed changes.

Reference:

Mann, JB., et al. Validity and Reliability of Hand- and Electronic- Timing for 40-Yard Sprint
in College Football Players. Journal of Strength and Conditioning Research, Ahead of print.